Came out today to perform preventative maintenance on a whisper heat Lennox furnace model #g2005/6E-150-7, serial #5899E 30821. Upon arrival I called for heat and the system started right up. I asked the homeowner if they have had any issues and he stated that everything has been working great. I took a combustion analysis test and received the following readings, o2 is 12.6% and the co levels are 6ppm. I powered the system down and removed the access panels. Cleaned out the burners and burner box. Tested the drain line and condensate pump with several bottles of water to ensure that there are no leaks or clogs. Checked all electrical connections to ensure that they are secure and in good condition. I powered the system up and called for heat. The blower motor amp draw is within the manufacture specs. The supply temp is 138°F. The system is operating properly at this time however due to the age of the system chud cannot Guarantee that there won’t be issues in the future. My professiona